Sirius Black and the Prisoner's Dilemma
by Avret
Summary: Sirius Black was just in it for the money. Bellatrix Lestrange was just following orders. Neither suspected that they would cause one of the worst catastrophes in human history. Continuation to HPMoR and GWatSI(Albeit with some changes to the latter), 3rd year.
1. Prologue: the butterfly effect

_It tumbles to the ground in a graceful arc, the hands that held it going limp, a figure blasted backwards. Prison bars shatter._

 _Something shifts in its sleep._

" _...death will be unleashed, and the red will herald the green."_

Prologue: The butterfly effect

*June, 1992: approximately 90 minutes after graveyard event*

A large black dog slowly rose from behind a headstone, blood dripping from its fur. Even Sirius's quickest Animagus transformation had not completely stopped the black threads from cutting into him, but his thick ruff and rapidly dropping height had saved him from the brunt of the damage.

A few seconds later, the dog's form blurred slightly, resolving into a human on hands and knees. Sirius stood, stepped over a body, and knelt to pick up his wand. With a muttered _episkey_ , his throat was whole once more. His physical ills healed, he was free to consider what he had just witnessed. He carefully walked to the altar before him and removed a small knife from a pocket on the inside of his robe, ready to stab if the girl so much as twitched. He'd come too far to be taken down by some overpowered undead thing. After a minute of watching, he stepped back, satisfied that she was truly unconscious.

As he walked backwards, he heard the rush of wind which heralded incoming broomsticks. He jumped back behind a nearby tombstone, eyes trained on the horizon. A few moments later, he muffled a laugh as he saw who Bones had sent. Aurors Nobbs and Colon were legendary in underground circles, known even to someone like him who'd spent the past 10 years in hiding. Their so-called special forensics team had a gift for deriving precisely the wrong conclusion from almost any piece of evidence. In fact, if what he'd heard on the grapevine was correct, the DMLE had bandied about the idea of charming each of them with compulsions to say the opposite of what they believed for a few years before the idea was vetoed. With a quick tap of his wand, he was disillusioned.

The broomsticks touched down heavily as the two aurors stepped off. They quickly began cataloguing the scene, in a way which men unfamiliar with Nobbs and Colon might categorize as professional, or even expert. After both men finished 'examining' the scene, they returned to the altar to discuss their conclusions. Sirius moved closer to listen. After almost dying, he needed a laugh. Who knew, maybe they would reveal something he could use.

"Nobby, this seems a right proper mess." Colon began amiably.

"That it does, Fred. Dark magic is always a nasty business." Nobbs replied.

"Not only that, Nobby. Why's there a girl here?"

"Well..." Nobbs responded sheepishly, "I don't know if you know this, Fred, but dark wizards sometimes...you know...do things to innocent young witches..." Insofar as Nobbs could be described to have human facial expressions, he was blushing.

"I knew that," Fred responded, eyebrows narrowing. "I've been on the force since you were still in your mother's womb, Nobby. I've seen everything these people do."

Nobbs nodded, expression penitent.

"I didn't mean to insult your policing experience, Fred. It's just..." he trailed off.

"Just what?" His partner demanded, leaning forward.

"Just..." A bead of sweat formed on Nobbs's forehead as he desperately tried to dig himself out of the hole he'd just put himself in. "Being the...shining beacon of morality which you are, you are sometimes a little bit...reluctant to assume the worst of criminals."

Colon leaned back, mollified. "I guess you're right, Nobby. That's why I have you here with me, right?" he said jovially. "After all, it can't be for your policing expertise."

Nobbs forced a chuckle before hastily changing the topic. "What do you think killed all the death eaters, Fred? I tried that priory incantaters spell that Bonesy showed us on you-know-who's wand, but it didn't work."

"Did you remember the swish and flick, Nobby?" Fred replied. "No spell works without the swish and flick."

"Are...are you sure that isn't just Wingardium Leviosa, Fred?"

Fred opened his mouth, but nothing came out. A few seconds later, he found his voice. "Yeah, that was it. I was just testing you, and you passed."

Nobby tilted his head, confused, then decided that Fred's idiosyncrasies were above his pay grade. "Anyway...if the spell didn't work, then it must not have been magic what killed 'em, right?"

Fred's eyes clouded over as his thoughts ponderously moved to accept this new fact. "That's a good point, Nobby. I remember a friend of mine who was on Azkaban duty this year-" both Aurors shuddered simultaneously, remembering their times on the Azkaban stint, "who mentioned that Bellatrix broke out using some secret muggle magic called...what was it...opposite reactionaries!"

Nobby's eyes widened. "So you're saying this muggle magic could've been what killed the death eaters?"

Colon nodded. "I'd never insult muggles, of course, they're the salt of the earth, but some of the stuff they do is downright creepy. I mean, imagine it: you're just walking along and then suddenly your head is opposite reactionaried right off your shoulders. It's unnatural. Now you-know-who's used their dread powers, who knows what'll happen."

Nobby thought for a second before his eyes brightened. "That's why you-know-who's hands are burned! Bahry One-hand was in St. Mungo's for weeks after the breakout and he was burned too! Opposite reactionaries must also give the muggles power over fire! And that means..."

"He tried to call up their power but couldn't control it," Colon finished. "That's...that's poetic justice, that is. We should get back to headquarters, Bonesy will want my report soon."

Nobbs nodded as the two strode away. As they mounted their broomsticks, he turned to Colon. "Have you heard about what happened back in Hogwarts? Word's getting around that someone took the stone from Flamel."

Sirius's eyes widened. The philosopher's stone had been taken? When? By whom? And, more importantly, how could he get his hands on it? With the elixir and gold, he could live his life like a king. He stood up, visualizing one of his many safehouses in preparation for apparition. It was time to retreat and plan. For the first time in years, he had a goal besides survival.

*June, 1993. Location: Mountains of Switzerland*

Bellatrix dove sideways behind an outcropping of rock, package still cradled protectively against her chest. A few curses whistled past the stones, harshly impacting the rocks behind her. From the size of the marks they left, these Aurors had definitely been aiming to kill, not to subdue. Bellatrix hadn't remembered the Swiss Guard being quite so brutal, but perhaps that was the effect of breaking into the Geneva branch of Gringotts and forcibly retrieving what her Lord had given her before he took her arm. If those people hadn't wanted to get turned into lifeless corpses, she reasoned, they shouldn't have stood between her and her Lord. Most of them were probably dirty muggle-lovers anyway.

Bellatrix flicked her wand a few times, surrounding the package in magical shielding before sending it to a pocket of dimensionally folded subspace only she could access. She didn't realize that these were the effects of the spell, of course. Her Lord had told her that this spell was to be used for safekeeping, and that was all she needed to know.

After making sure her package would remain safe, she stood up from behind the rocks, body already wreathed in multicolored, multifaceted shields. Even without the use of her left arm, Bellatrix Lestrange was still a force to be reckoned with, and she was about to give these pathetic aurors an object lesson in angering a superior magic user. With a wild laugh, she launched herself over the rocks, wand already out and firing.

The one survivor of her attack, found 30 miles away with almost all his bones broken, later described his memories thusly: "I...I couldn't see anything clearly. She stood up and laughed and we readied our wands on her. Then...then the world was fire and destruction. I could have sworn that there were more copies of her spells than there were aurors on our side."

*Approximately 47 seconds later*

Bellatrix stepped over the body of the last auror, brushing the ashes of the second to last off of her dress. She looked up at the sky, trying to pinpoint the location of the one unfortunate who had stepped into the path of her _Singularius Nex Maximus Clonizavit_. After a few seconds, she decided it wasn't worth the trouble to shoot the auror with a Killing Curse in midair. After all, she had a job to finish. She pointed her wand upwards and whispered a quick spell to summon the dark mark where she stood, burning it into the air above her. That would hopefully keep the aurors busy for a while. After looking over the scene once more, she apparated to the nearest of the Dark Lord's safehouses. Once she checked over the place for magical surveillance and reassured herself that the only bugs there were ones she herself had placed, she resummoned the package. It landed softly on the ground, magical shields cushioning its landing before winking out. She knelt next to it and read the message on the parchment wrapping once more.

" _My dear Bella,_

 _You do, of course, know that I am immortal. However, at times, preservation of my immortality requires certain sacrifices. Therefore, if I am ever unresponsive for a year, open this package and put on the locket within. Then, read the runes below."_

Bellatrix flicked her wand once, resummoning a perfectly accurate clock already linked to a preprogrammed date. It had been a long year of waiting without him, but it was his will.

The moment the clock flashed green, she slowly opened the package, lovingly putting on the locket. She lifted the note again, carefully reading the runes on it. While she didn't know it, these runes were a precise transliteration of a parseltongue statement.

" _I conssent to indefinite posssesssion by the sspirit contained within thiss gold."_

Suddenly, the locket glowed as the magic held within it leaped into life.

 _Initialize recovery procedures._

The spell first activated an initial failsafe, fully backing up all information it held.

 _Step 1: Memorial comparison._

The spell awoke the horcrux 1.0 consciousness within it for long enough to link up to the horcrux 2.0 network to which that consciousness was connected. It then compared the network to its recently stored version of the network, checking for any differences.

 _Alert: Horcrux memory compromised! Failures detected throughout memorial system!_

The locket sent out a magical alarm pulse to every other artifact hooked into its system, causing them all to compare their own backups. After the other artifacts reported similar results, the locket moved on to the next stage of its programming.

 _Step 2: Release Horcrux consciousness._

Bellatrix's eyes widened as she felt an immediate rush of magic into her. Unlike most magics, this spell felt strange, yet hauntingly familiar. A few seconds later, she collapsed, eyes flashing red. When she stood up, her mind was no longer in control.

Voldemort rose, taking a few steps to get used to his new body. With an almost contemptuous flick of his new wand, he conjured a silvery arm which fit itself onto the stump by his shoulder. After he was satisfied at his magical prosthetic, he carefully opened his mind to the Horcrux 2.0 network, examining it for inconsistencies. What he found shocked him. The sheer amount of memory gaps looked almost like someone had obliviated him. On its own, this was strange: after all, why would someone have obliviated him rather than killing him outright unless they knew his secret? When he combined that question with the memories he could salvage, the picture grew downright alarming, with one person at the center of the whole event. And so, as he walked forward and let the Horcrux 2.0 system repair itself from his memories, one thought was clear in his mind: Find Harry James Potter-Evans-Verres.

A/N: And so it begins. Sadly, I won't be able to update this that regularly for a while, though I hope I will be able to update by the summer.

Please review!


	2. Dissimulation, part 1

Arc 1: Reconnaissance

Chapter I: Dissimulation, part 1

 _Polyjuice potion seems to be based on two separate 'save states'. The first save state activates the moment the item(hair, skin, or similar; any DNA source seems to be a sufficient marker) is taken from the target. At this point, the target's current physical condition, including any diseases(whether symptomatic or not) and fatigue, is saved. Mental condition, including emotions and any item shown to be part of the resurrection stone's recall, does not appear to be preserved at this stage._

 _The second 'save state' occurs when someone takes the potion. At this moment, all aspects of their condition are saved. When the potion's duration ends, their body returns to this original condition in a process that takes approximately 2 seconds and is uninterruptable. 'Polyfluis Reverso' appears to instantly activate this process._

 _Further investigation of the possibility of stasis using the potion is likely necessary._

 _-Research log(Section IV: Bodily modifications), Tower of Hogwarts, June 1993_

XxX

August 25, 1993, 9 pm: 6 days before Hogwarts opening

Colin Creevey looked to both sides nervously. Even though he had received a Hogwarts permit to work with Sapespeck over the summer in a limited capacity, he still couldn't shake the feeling that he was being watched. If any of his old muggle friends saw him, the consequences for the statute of secrecy could be horrendous. After reassuring himself that there was nobody near him, he laughed at his paranoia before readying his wand.

"Cognitio Mentis!" After the unpleasantness of last year, Flitwick had taken a month to find some charm that would allow for non-Parseltongue speakers to use the language. Eventually, he had found a substitute. The spell, originally intended for use by career duelists who wanted to refine their spells and tactics as well as avoid traps, allowed its caster to perceive all direct results of spells in their vicinity for a period of time, even those that were normally hidden. One of it's useful side effects was giving the caster the ability to understand Parseltongue coming from Sapespeck.

"Sapespeck!" A green point blinked into existence in front of him. He pulled a small pebble from his pocket and tossed it forward. The green speck flashed and emitted something that was both a sound and not at the same time, and the pebble stopped midair, dropping straight down.

Colin grinned. Harry was right, the spell definitely could produce pressure waves. Now, for the next step. He dropped to his knees and picked up the pebble before standing and readying his wand again.

"Sapespeck Maxima!" 16 specks flashed into existence in front of him, grouped into 3 pairs and one clump of ten. He lifted the pebble again, bringing it into line with the first pair. He wasn't quite sure about this part, but Harry had gotten really excited about something he kept calling a 'Magi-optic semaphore system lacking the downsides of the protean charm' and 'the wizarding world's ARPAnet'. As the pebble moved into the line formed by the first pair, the first speck of the pair flashed and hissed, causing a chain reaction in the rest. A few moments later, the second speck flashed at him.

" _Time for messsage: two partss in thoussand."_

Colin smiled. It looked like that communication was definitely faster than sound, but slower than light. A lot of that could be processing bottlenecks, though. He'd need to work on that. As he lifted his wand to dispel the specks, he doubled over. It felt like a sword was stabbing him in the mind and cutting away at his identity. As he collapsed, eyes watering with the pain, a black dog seemed to materialize from the shadows before blurring into a man. The man walked over to him, looking with no small amount of pity at his writhing body.

"Look, kid, I'm just going to say in advance that I wish it didn't have to be this way. If it's any consolation, this isn't personal. It's just business."

The last thing Colin saw before blacking out was the man pulling out a pair of scissors and cutting off a lock of his hair. Then his world went dark.

Sirius dropped the young wizard's hair into a flask of Polyjuice, grinning as it turned a light blue. It looked like this one would taste reasonably good, unlike some of the other jobs he'd done. He downed the vial, grimacing as his body warped and shrunk until it matched that of the child currently passed out on the dirt. He never got used to that feeling, At least the potion preserved his magic and he didn't need to deal with some...he searched through the information his Legilimency had brought him to find the age of the child...some second year's magic and the Ministry's damned trace. That would be intolerable.

With a flick of his wand, Sirius' clothes became identical to that of the child. With another flick and a muttered word, the boy's body and the flask disappeared. He wouldn't need them for a while. A third cast changed the appearance of his wand to that of the boy's. Now for the fiddly part about stealing someone's identity. He concentrated, bringing the information he'd gleaned from Legilimency to the forefront of his mind. He lifted his wand, pointing it at his own temple while focusing on linking the duration of his next spell to that of the polyjuice.

"Confundus!"

Colin blinked a few times. Why did his head hurt? And what was he doing? After a few seconds of confused looking around, he caught sight of the specks and relaxed. He was experimenting with Sapespeck tonight, of course. If his current fuzziness was anything to go by, he probably needed to get some sleep. The research could wait.

When he arrived back at his house, his father waved to him from his seat by the television.

"How's your summer project going, Col? Anything you can tell Dennis about?"

"Not yet, Da." Colin smiled. His little brother was so eager to learn about magic, and Colin couldn't really blame him. When he had first found out about magic, he had been so excited that he'd almost...what? Why couldn't he remember what had happened?

His father noticed his discomfort.

"Col, are you ok? You look a bit pale. Is this something to do with magic?"

Colin shrugged.

"Probably not, Da. I'm just feeling a little tired, is all. I'll be better in the morning."

"I'll hold you to that, you know." Mr. Creevey's eyes twinkled, and Colin laughed.

"I know, Da. Good night!"

Colin went up to the second floor and into his room, falling into a dreamless sleep almost the instant his head hit the bed.

XxX

August 28th, 1993, 10 am: 3 days before Hogwarts opens

"Mrs. Babbage, was it?"

The voice jerked Voldemort out of his reverie. Somehow even a wizard with his mental reserves couldn't manage to stay focused in the Ministry's Property Allocations office. There was something about the place that seemed to drain the energy from anyone inside.

He lifted his head.

"Yes, that's me. Can I come in?"

The attendant at the door nodded.

"Yes, Mr. Rimble will see you now."

Voldemort stood, still a little shaky on his feet after this most recent set of bodily modifications. While it wasn't strictly necessary to modify his height and weight to avoid being seen as Bellatrix(after all, he had of course already changed his face and hair color) it never hurt to be too careful.

The attendant led him down a short hallway into a small room which almost looked like a cubicle. Everything about the room, from the N.E.W.T scores posted on the wall to the obnoxiously shiny nameplate on the desk in the center, suggested that its occupant felt a good deal more pride in his pointless middle manager job than was deserved. A few moments after he sat down, the desk's occupant turned to face him.

"Good morning, Mrs. Babbage. My name is James Rimble, and I am your ministry-assigned Property Acquisitions representative. Why are you here this morning?"

Voldemort sighed. The ministry, it seemed, was as delightfully incompetent as it had always been. Ah well, at least he could blow off some steam winding up idiots.

"Well, Mr. Rimble, it should already say that in my file. But, since you don't seem to have that, I'm planning to move into Hogsmeade."

The man's face reddened slightly.

"All right, you don't need to be snarky. I just wanted to make sure your reasons matched with what we had on file."

"To make sure I didn't lie about my reason for coming? I somehow doubt that happens enough to warrant this."

Rimble's eyes flashed with annoyance.

"Look, ma'am, that's not what we're here to talk about. I'm going to need to ask you to stop being confrontational."

Voldemort raised his hands in acceptance. Time to soothe some ruffled feathers.

"I'm sorry, Mr. Rimble. I've just had such an abominable time getting here that I've lost some of my tact."

The man laughed companionably.

"I can understand that, Mrs. Babbage. I'll try to get this done as quickly as possible, ok?"

"That would be excellent, thanks."

Rimble smiled.

"Ok. Now, before I give you your permit for Hogsmeade residence and access key to the wards, I'm going to need you to answer some questions for our files, ok? Security's gotten a bit tighter around there lately, because of the Tower and all."

Voldemort nodded.

"Of course. Ask away."

"First off, have you taken any trips in the past 5 years?"

"Yes," Voldemort nodded. "I went to visit my son on the Continent around a month ago. He lives in Paris. I left on the 25th of July and returned on the 2nd of August."

Rimble pulled out a file and glanced at it.

"Ok, that checks out. Thanks for giving me the extra information, it cuts out some of the other questions I'd have needed to ask. Why are you moving to Hogsmeade?"

"Some of my relatives live there and they've been after me for a while to join them. Now that my son's out of the house, I can move there even though it means taking a smaller home. Also, with my husband gone, I'm a bit low on income, and Hogsmeade's cheaper than London."

The man paused for a moment to update the file before turning back to Voldemort.

"Might I ask what happened to your husband?"

"He worked in the Department of Mysteries, doing god-knows-what. There...was an accident. I never even got to see the body-" It only took a little effort to bring tears to his eyes and fake choking back a sob.

Rimble's eyes widened.

"Ma'am, I didn't mean to bring back sad memories. I'll fast track you through the approval process, ok?"

Voldemort nodded, wiping the tears from his face.

"Thank-thank you, James. When can I move in?"

"I'll do my best to make sure you can by tomorrow, Ma'am. Any more questions?"

"No. Can I go?"

The man nodded and Voldemort stood up, leaving the room. That had been about as easy as expected.

A/N: After many months, SBatPD is back! I've many, many plans for this story, and hopefully I can see them all come to fruition. There are some slight changes from GWatSI, mainly to characterization.


	3. Dissimulation, part II

Chapter II: Dissimulation part II: Sufficiently accurate simulations:

 _The confundus charm is unique among nearly all charms in its method. Like many other spells(such as, say, Imperio) it is meant to control the actions of the victim. However, unlike Imperio and Legilimentic control, the spell does not implant low level hypnotic commands into the mind of the subject. Rather, it appears to override parts of the subject's consciousness entirely, replacing those portions with the caster's desired thoughts, memories, and emotions. This makes the spell simultaneously far more dangerous and more versatile. On the one hand, an inexpert caster can leave their victim a drooling, unrecoverable wreck, replacing their minds with half-built thoughts. On the other hand, an expert can change a person on a far more delicate level, slightly modifying various parts of their minds to create the perfect sleeper agent. In effect, the confundus charm is the scalpel to Imperio's hammer. It takes far more practice to use, but can do far more._

 _To explain the relevancy of the charm to our mission, consider this: Confundus works on any human being with a magical core, including those who have unfortunately been Kissed or who are brain dead. A skilled legilimens can recover enough information from a person's mind to emulate them through a confundus in minutes, if not less. The implications are clear. Magical transfer of consciousness is possible._

 _-Research log, section X: Conclusions and evaluations. Subsection II: Consciousness emulation(Tower of hogwarts, July 1993)_

XxX

August 31, 1993: 1 day prior to Hogwarts' opening

Colin struggled to wake. It looked like he had had the dream again. His eyes opened and he groaned to find that his sheets were soaked with sweat, just like they had been for the past 5 nights. He really needed to figure out what was going on because this kind of sleep deprivation would seriously screw up his research and could damage his mind. He closed his eyes, trying to reconstruct the dream. After a few seconds, the dream flew back to him, playing behind his eyelids almost against his will.

 _Hands too large extend from a body that's too big, it's TOO BIG and he can't control it and it's reaching for another him, that's another HIM there on the floor and he looks sick and doesn't move. The hands move and a bit of the other him's hair falls off and he can't understand why any of this is happening, he tries to think about it rationally like Harry taught him but his brain feels like it's broken and missing pieces and before he can even start thinking about that the hands twitch again and there's blue liquid flowing down his throat. Then there is darkness._

His eyes snapped open. He hadn't seen the blue liquid before. That gave him something to work on. He feverishly unzipped his bag and flung out the carefully packed books until he found what he was looking for: his potions textbook. He flipped to the image-based index(one of the features of the new books, Harry had insisted on it for some reason and for the life of him he couldn't remember why, he couldn't remember anything like he should be able to but now wasn't the time to think of problems, now was the time to solve them) and scanned down the page, trying to find anything that could possibly be the liquid from his dreams. Eventually, he caught sight of two potions in a section marked 'Advanced: Only present for demonstrative purposes'. The first was a dark blue, slightly different from the color in his dreams: the Draught of Peace. According to the textbook, the potion served as an emotional depressant and a sedative. Given his dreams, that...didn't seem likely. On the other hand, maybe the weird color was because the potion was prepared incorrectly.

The next potion threw him for a loop: Wolfsbane. The potion was a bright blue, just like he remembered from his dream. Also, its user needed to take it every night for a week before the full moon. If the sky the night before was anything to go by, the full moon would be the next day, if not earlier. That didn't explain the hands, and the other him, but it seemed to make a kind of sense. There was one thing that he needed to check, though. With a goal in mind, Colin walked downstairs and greeted his father.

"Good morning, Da."

Mr. Creevey smiled, though some concern still lingered in his eyes. He knew Colin wasn't sleeping well.

"That it is, Col. How are you feeling?"

Colin shrugged.

"A bit better, Da. How's Dennis?"

Colin's father beamed. "He's doing excellently. He sent me a letter this morning saying that he'd just finished getting the last of his books."

"That's good." Colin fell silent, staring at his father for a few moments.

"Yes, son?"

"I have a question: when I came back from research Wednesday night, did you see any scratches or cuts on my body? Small scrapes, even?"

His father tilted his head for a few seconds, thinking.

"No, son, I can't say you did. You were really pale though. It looked like something had scared you out there. Why?"

"I think...I think I might know why I've been having bad dreams." Colin hesitated.

"Why?" His father urged.

"I...I might be a werewolf. I don't know for sure, and I think that I've been taking potions to fix it. I think that I've been forcing myself to take those potions before making myself forget the experience."

Mr. Creevey's eyes widened and he fell silent for a few seconds, clearly stunned.

"Son...you want to run that by me again? I think I must have misheard."

"Sure, Da. See, the morning after I got home, I checked my wand, and the most spell I'd fired that night was meant to implant commands. Also, I've been having dreams where I drink a potion that looks like one called Wolfsbane. I think I got bitten by a werewolf out there and then used the spell to make sure I'd drink Wolfsbane and not remember drinking it, but I screwed it up slightly so now I remember in dreams."

"...what exactly should I be doing about this, Colin? It sounds like you're in danger, and I have no idea how to help. Should I write the professor that took you and Dennis to buy your books?"

Colin sighed.

"I don't know if there's anything you can do, Da. I don't want to tell her what I think it is in case I'm wrong. Look, I'll be at Hogwarts tomorrow night, and I'll ask the healers to check me over, ok? If this is what I think it is, then I'll be fine."

His father nodded unwillingly.

"If you say so, Col. If you say so."

"Nothing's going to happen to me this year, Da." Colin smiled. "I promise."

XxX

August 31, 1993: one day prior to Hogwarts opening.

9:52 am

 _Stupefy et Signa!_

A red bolt flickered along a dark hallway before sharply curving in midair to slam into a seemingly nondescript wall. A few seconds later, a high, clear sound rang out and a green light shone for a brief moment before shutting off. Harry James Potter-Evans-Verres took note of the light for a moment before turning to a notebook and activating his dictation quill.

 _Test 101a result: Strings of enchantments can be linked to specific casting words and gestures as a compression method. This suggests that spells as we know them are based enough in the mind of the caster that the caster can, to some extent, combine various spells into a new spell._

After he fell silent, he leaned back against a wall as his eyes closed. Combining spell strings was a taxing mental exercise, even for him. Especially given his particular...versions of the task. On the other hand, he was yielding results! In only a few months, he'd have some basic enchantment sequences finetuned to the point that he could teach them to others!

As he relaxed, Hermione appeared out of a seeming void next to him. That particular trick had taken her a few months and a lot of research into the refractive properties of pressurized air.

"Harry, are you ok?"

He opened his mouth to answer, but she cut him off.

"Why am I even asking you this question, of course you aren't, look at you. You've been working on this one set of experiments for how many hours straight now? 30? 40?"

Harry sheepishly nodded.

"45 or so, actually, but that isn't especially relevant. I did get some sleep in the interim period. And I need to finish this as soon as possible! Spell strings could massively hasten the stasis process! My work might be tiring but I'm saving lives."

Hermione sighed.

"That was true of the polyjuice research too. And the low level command system for healer reflexes. And the consciousness emulation systems. In fact, if I'm not wrong, every project you've been working on since the Amortentia...incident fit that qualification, did they not?"

"And?"

"Harry, you can't keep doing this to yourself!" Hermione snapped. Her magic seemed to press down on the room. "You're burning yourself out, and I won't just sit by and watch it happen. You won't do this alone, Harry-" She cut herself off before her next words could leave her mouth but they reverberated in her mind. 'because I swore on my life and magic that you'd never have to.'

He caught sight of her expression and whitened.

"Hermione, it's ok. I'll pull back on the experiments for now. I just had my first successful result, anyway."

Her demeanor instantly changed and she stepped closer to him.

"Really? What was it?"

He smiled and raised his wand.

"Observe."

He flicked his wand 3 times at the wall to his left.

 _Luminos! Stuporfy tenues! Lux sopitum!_

The wall lit up briefly before a stunner slammed into it. A moment later, the spot hit by the stunner glowed a faint green. Hermione tilted her head, confused.

"Yes? You've shown me this combination before. Is there something I should be seeing?"

Harry grinned and twisted his wand once.

 _Stupefy et Signa!_

The same set of effects repeated themselves at a slightly faster pace. Hermione's eyes widened as she smiled.

"You figured out spell strings! What was causing the issue?"

"Something about holding every spell in mind simultaneously was a mental stumbling block. I ended up bypassing it by-" Harry's voice froze. A few seconds later, he cursed under his breath.

"Looks like the Vow blocked that one. So be it."

"It's that dangerous?" The secondary, real question was not missed by either of them.

"I don't know, Hermione. I was able to think about teaching healers to do it. I just don't know. Anyway, why'd you come to see me?"

She smiled again, a smaller, weaker smile this time.

"I wanted to remind you that the school year starts tomorrow. Ready for third year?"

A/N: Sorry for the slight delay, the second half of this chapter was difficult to write. The next chapter(either Dissimulation III: Foreground and Background, or Foregrounds and Backgrounds I) should be out in about 2 weeks.

I feel now's as good a time to say it as any: all facts in this story(whether about the canon-verse, MoR-verse, the stuff I'm preserving from the GWatSI-verse or about physical stuff like full moon) are meant to be accurate. If you find mistakes, please tell me(sources if you would).

Plotwise: The chapter title is directly relevant to all three sections of the chapter, and figuring out how will help the reader figure out Harry's method for spell strings.

Please review!


	4. Foreground and Background

Chapter III: Foreground and Background, I

 _House elf magics appear to be based on a mechanism similar to that of accidental magic. Both of them override almost all warding systems, and both allow for power greater than that of many basic spells. Additionally, the possible spell effects available to either system are similar. However, the magic of house elves can be controlled by the wielder and directed._

 _Polyjuicing a house elf into a human form will succeed. The house elf will keep their magical ability and compulsions, and clothes in this form will still free the elf. One result discovered by testing indicates that among the magics that house elves can cast is a permanency effect which will extend the duration of a potion or effect for as long as the 'spell' is held. Experimentation on accidental magic has yet to confirm the presence of such an effect within the range of possibility, but it cannot yet be ruled out. Further experimentation in this area has been postponed until holding mechanisms for transformed elves can be devised. For further information, consult Appendix B, section C: Operation Epsilon._

 _Providing a wand to a house elf will greatly increase the power of their cantrips and decrease the cooldown time of their teleportations. However, any attempt to cast spells will fail and cause a magical backlash on the elf while activating their punishment compulsions. This seems to be an artifact of the spells laid on the elves. Further experimentation into this area has been discontinued pending the discovery of ways to override punishment compulsions._

 _House elves can be commanded to follow anything that a human mind can understand. House elves can understand commands from their master in any language. House elves can transmit commands from their master to any other elves that master controls provided they are so ordered. Further experimentation on this area has been postponed due to Protocol V._

 _-Research log, Appendix A: Postponed Experiments, Section III: Magical Creatures, Subsection I: House Elves(Tower of Hogwarts, May 1993)_

XxX

September 1, 1993(Hogwarts opening day), 9 am

Colin strode through the platform, grinning as the magical warmth of the station replaced the cold outside. He was back. As he walked toward the train, Ginny came up alongside him, grinning.

"Colin!" She stood before him, smiling happily. She opened her mouth to say something, hesitated, then surprised him with a tight hug. Taking a step back, she blushed and picked at the hem of her sleeve. "It's nice to see you."

Colin's eyes widened.

"Y-you too," he stammered.

"Um...How was your summer?"

His eyes gleamed and he smiled.

"It's been excellent! I've found out so much about Sapespeck, and a few nights back I managed to get the network up and running-" He stopped talking as though he was punched in the throat, suddenly aware of what else had happened that night. Could he tell her? What would he even say? 'I think I might have become a werewolf and wiped my own memory?'

"Really? That's amazing!" She said. Ginny tucked a strand of loose ginger hair behind her ear and smiled brightly.

Her smile inspired him to try to explain what had happened. After all, if anybody would understand loss of memories, she would, right?

"Look, Ginny, something happened to me a few nights ago. When I was working on Sapespeck, I was attacked, and..." He fell silent, unsure how to continue.

Her eyes widened. "What?!" She whispered. Ginny glanced around them, then took a step closer. "Are you ok? What happened?"

"Right after I finished my work on the 25th, I felt this massive pain in my head." He pointed to the front of his skull. "It felt like someone was cutting away with a knife at my...at my me. Ever since then, I've been having these horrific dreams every night, dreams that I'm not myself, that I'm lying there unconscious in front of me...this isn't making any sense to you, is it."

Her face darkened, becoming unsettlingly austere. "Colin, that sounds really serious. I... You need to talk to someone. What you're describing? Those are symptoms of possession. "

He froze, paling rapidly.

"P-possession? Are you sure? But I didn't touch anything magical besides my wand, and nothing strange has happened to me during my dreams. The only odd thing going on is..." His eyes widened. "I've been missing memories."

Ginny shook her head. "I'm not an expert on how possession works…" Her expression grew colder, "just how it feels. And if you've been missing memories, then it's definitely a lot bigger than nightmares."

"I know. As soon as the feast ends, I'm heading to Madam Pomfrey."

"Pomfrey?! Go to Professor Mcgonagall! Or Slughorn!"

"And tell them what, exactly?" Colin snapped. "That I'm having dreams and my head hurts? Look, I'm going to go to Pomfrey first and see what she says and then, if she actually thinks there's something dangerous, then I'll tell the Headmistress."

She looked sceptical, but shrugged. "Fine, but let me know, ok? And if you ever need anything..." She absently raised a hand to the silver crucifix charm hanging delicately by her neck.

Colin's wand flicked through two complex motions and he grinned as a green mark appeared in the air near her.

" _If I need ssomething, all I musst do is whissper."_

She smiled. "You got it."

The train's harsh whistle suddenly sounded, startling the two.

"I'm sorry, but I'm not going to be able to sit with you on the train," Colin said sheepishly. "Draco wants me to report in. Something about the summer research. You understand."

Ginny nodded. "No worries. I'll see you at the banquet?"

"See you then."

XxX

September 1, 1993, 12 pm

Voldemort pulled back from his worktable, hands flicking in quick motions and extinguishing a handful of golden sparks. He almost had the spell that time, if it hadn't been for a burst of emotion from the other side of the bond. If he had had a few more seconds...he laughed sharply. Lack of his ritual seals would just make the whole process more fun. Anyway, his concentration was starting to flicker. A break was warranted.

After a quick meal, he returned to his worktable and closed his eyes briefly before quietly speaking a word from a language no modern lexicographer would recognize, calling up a faint yellow mist. As he watched, the mist organized itself into a series of hundreds of small interlocking circles, two of which faintly pulsed. With another word, the darkened circles vanished and the two glowing circles expanded to cover the entire table. He peered closer at the circles and curled his index finger. The yellow vanished to reveal hundreds of interlocking black words which seemed to be borrowed from every written language. With a tsk, he pulled out a line of connected characters from a section written mostly in kanji and read them over carefully.

"Hyōmen ni yotte, kokoro to kokoro no setsuzoku...Ah." He sighed. Even after 9 years of perfecting the ritual, he still managed to make the most idiotic of grammar errors. Really, it reflected badly on him. Anyway, the change was reasonably simple, all it would take was a few minor edits to the ritual. His wand flicked a few times, spinning out new kanji to replace the old before reading over his new handiwork.

"Kokoro to kokoro no setsuzoku, hitsuyōna toki ni yowai o miru koto o kanō ni suru kyōryokuna."

That should solve the pesky problem he had had two years ago with reading the child's emotions and thoughts. With another flick of his wand, the characters were covered by the yellow circles again. With another flick, the bright circles rejoined the dark ones. A moment later, Voldemort raised his wand.

"Aldaketak sartzea etenik gabe eta egonkortasuna zaintzeko."

He would have preferred not to speak aloud for magic of any sort, but ritual magic of this sort was dangerous enough to require his full concentration and any help the mechanisms of his superiors could give him. Anyway, his wards would prevent any sort of magical scrying and anyone who did look in would merely see an old woman muttering in Basque to herself. A totally normal activity for someone with Spanish ancestry, like Mrs. Babbage.

As the spell took effect, both circles glowed and he felt a slight pull at his magic. A moment later, he felt a presence at the back of his mind. When he pushed on the presence, it yielded, and he fell through to an entirely different mind. After catching just a few snatches of thought, he grinned and sent himself back through to his own mind. Out of all the justifications he gave for being a Dark Lord, he couldn't deny that the sheer thrill of a plan coming together was at the top of the list. Harry James Potter-Evans-Verres would soon know the dangers of trying to eliminate someone of his caliber.

A/N: So, as you can probably tell, the magic system is going to be a lot more fleshed out here. A _lot_ more. Those who wish to translate the ritual segments and the Basque are welcome to. It will come back in the plot.

Meanwhile, I have to give serious thanks to kittykatrosetta for her aid with the Ginny segments of the chapter. The dialogue would have been far worse without her.

The next chapter, Re-entry, should be out before the 18th of October, and hopefully by the 11th.

Please review!


	5. Re-entry

Chapter IV: Re-entry

 _One of the flaws of even the most competent bureaucracies when not all information is automatically logged is that, at some point, a lower level employee has to decide whether to pass information up the chain to their superiors. Normally, this is good; it keeps the higher-ups from becoming overwhelmed by unnecessary information. However, at times, it means crucial pieces of the puzzle fall through the cracks. On September 1st, 1993, Professor Remus J. Lupin performed the standard magical nullification spell to deal with an unfortunate buildup of magical energy in one of the compartments on the Hogwarts Express, caused by what, for all intents and purposes, appeared to be an outburst of accidental magic from one of the second years. A spell so standard, in fact, that he had almost forgotten about the entire incident a few months later._

 _Approximately 10 hours later, Professor Horace Slughorn used the same spell to nullify a Slytherin first year's accidental magic. 2 hours later, the event faded into the back of his mind. Within those 12 hours, Hogwarts' best chance to prevent the events of the next year had vanished._

 _This illustrates the importance of efficient information systems logs in a magical security system. Events such as that of 1993 would not have happened under proper supervision._

 _-Auror Handbook, Edition 49(Published 1999), Chapter IV: Effective Security Systems_

XxX

September 1st, 1993, 12 pm

" _Phoenix's egg."_

The wall on the side of the Headmistress's office slid open, and Harry strode through the passageway, shaking his head to clear the reverberations of the magical passphrase. Once he reached the inside room, he turned to the right wall, stepped forward three steps, and pointed his wand at the passageway. Normally, he wouldn't activate Dumbledore's secondary protection magicks when he might need to call Hermione for help, but these experiments were far from a normal day's.

" _Phoenix reborn."_

An orange haze shot out of a sigil painted on the doorpost of the passageway, sealing the entire chambers in a magical stasis field and preventing anything, physical or magical, from entering or leaving the room unless it was specially keyed into the spell. A few seconds later, the field glowed a soft blue and began to magically ventilate the room by switching air inside the field with air outside it. Harry dearly wanted to know how much power that kind of spell took and if it was feasible for a third year to learn, but the unbreakable vow had stopped any sort of research into that area of magic. Quite sensibly, to be fair, as while he didn't know the potential consequences of messing up a time-space stasis spell, he imagined the results would be...catastrophic.

Harry pulled a small lump of steel from his pocket and set it down next to a notebook and dictation quill left there from the last experiment. He concentrated on visualizing a long glass tube, and touched his wand to the lump. A few seconds later, the steel was transfigured. Step one, complete.

Next, he visualized a loop of thread and transfigured the glass into the thread. A prior series of experiments involving magical items and enchanting transfigured objects had confirmed that, in some sense, magic recognized a transfigured item as two things: the item it currently was, and the item that it was connected to by use of some magic and visualization to connect Source and Form. It was time to test one of the corollaries of that hypothesis. With a conscious mental effort, Harry cut off the magical connection between Object:'Steel Lump' and Form: 'Glass cylinder', careful to sustain the transfiguration keeping the thread from morphing back into the cylinder. The thread seemed to shimmer once or twice as he broke the connection, and once took on a slightly glassy sheen, but eventually returned to normal.

Once the thread seemed to have stabilized, Harry broke the transfiguration on the thread. It abruptly flickered back into a glass tube, but something seemed...strange about it. He stepped over to the cylinder and gingerly picked it up, but it remained stable, weighing approximately the right amount. He turned back to the notebook and began speaking.

" _Test 204a result: Transfiguration by connection breaking appears to be permanent, at least physically. Something appears off about the result. Further examination required."_

He faced the cylinder again and raised his wand.

"Crystferrium!"

The spell extended outwards, and Harry could feel his magic take hold of the glass, beginning to reshape it into steel, when his magic abruptly failed. His eyes widened and he flicked his wand again.

"Locomotor Crystal!"

Again, the magic extended outwards and seemed to partially catch on the cylinder before failing. Harry's eyes widened. What the hell was going on? There was no reason that the glass shouldn't be responding, unless... He grinned, then laughed sharply. His wand went up again.

"Locomotor Ferrous!"

The cylinder twitched once or twice, then slowly rose into the air. Harry's jaw dropped and he started chuckling. It seemed that this method, while time consuming, certainly had...fun effects. He definitely needed to record this result.

" _Test 204b result: Transfiguration by connection breaking preserves the magical identification of an object while modifying its physical properties. This physical modification appears to be permanent. Further research is required."_

He turned back to the cylinder, but the stasis field flashed once, warning him of an approaching visitor. He turned back to the front door and saw Hermione waiting outside the field, tapping her foot impatiently, her arms folded over her chest. Harry shrugged apologetically then twisted his wand slightly.

" _Phoenix's flight!"_

The field flashed once and Hermione appeared on the other side, orange light cascading off of her as the field accepted her in. She brushed off a few lingering sparks, body moving gracefully. Harry's eyes widened slightly, mind momentarily taken from research by the realization that Hermione had indeed gone a ways through puberty.

She noticed his slightly widened eyes and grinned.

"While I can't say this isn't nice for my self esteem, I did want to see what you were researching. It's not like you to vanish so suddenly this close to the new year." A bit of concern tinged her voice.

He nodded and turned slightly to face the cylinder.

"Accio cylinder!"

He caught the cylinder deftly. A moment later, he turned back to Hermione.

"Try summoning this glass cylinder from me by identifying it by its element, if you would. "

She nodded confusedly.

"Ok, though I don't see why that matters...Accio glass!"

It seemed to twitch slightly, almost invisibly, but failed to move otherwise. Her eyes widened.

"You developed an anti-summoning charm?"

Harry grinned.

"Oh, this goes a good deal deeper than _that_. Try to use a glass-targeting spell, if you would."

Her eyes widened and she flicked her wrist.

"Locomotor Crystal!"

The cylinder failed to move. Hermione froze, processing the new information. There were currently two possibilities. Either, Harry had managed to derive multiple unknown countercharms, or...she gasped.

"You figured out how to change an object's magical identification, didn't you."

Harry smiled.

"Not exactly. I figured out how to permanently change its physical identification while preserving its magical identification. Behold...Transfiguration 2.0."

XxX

September 1st, 1993, 5 pm.

The train gradually glided to a stop and Colin quickly stepped off. If he wanted to make it back from Madam Pomfrey's in time for the Evening Feast, he'd need to hurry. Especially given whatever it was that had happened on the train. He wasn't even sure how to describe it, it just felt like the entire world outside his car had skipped forward a few seconds, while everyone inside the car had remained in the same position. Was that possession? Was Ginny right? As he reached the carriages, he hopped into the first one available. The moment he got inside, the carriage took off at a brisk pace, its mysterious driver seeming to sense Colin's agitation. He was glad about that, at least. He didn't want to have to talk to anybody else until he was certain he wasn't going to somehow be the vehicle for some Dark Lord's plans.

A few minutes later, the carriage pulled up to the castle and Colin stepped out. As he approached the entrance, the Headmistress seemed to appear from thin air near him.

"Mr. Creevey, we have some new security procedures this year because of what has happened in prior years. I was going to wait til more students arrived, but seeing as you're a few minutes ahead of them I will tell you now."

Her wand flicked once, and a sheet of moving water blurred into visibility from atop the entrance.

"Due to the generosity of certain concerned parents and the ingenuity of certain of our own students, we have been able to procure a permanent segment of the Thief's Downfall. Any student entering Hogwarts from outside the grounds will be required to pass through the water to be granted entrance."

Colin's eyes widened.

"What does the waterfall do, headmistress?"

Her tone changed, becoming more like that of the teacher she once was.

"The Thief's Downfall is an ancient magical device, created by wizards centuries ago. It's water removes all magical concealment, ends all compulsion, and breaks all illusions. Until this year, it was in the deepest vaults of Gringotts, protecting the possessions of the Noble Houses of Britain."

Colin relaxed. Even if he was possessed, this would break that possession. He would be himself again.

"So, how do I do this, headmistress? Do I just walk through the water?"

She nodded and her eyes glittered with suppressed mirth.

"Yes. Though, I must say, it's not often I see a student incredibly eager about _removing_ deceptions."

Coling laughed sheepishly and stepped through the water. It parted over his shoulders, somehow still refreshing despite the already brisk day. Once he left the sheet fully, his body dried instantly. That was a nice feature. He calmly stepped forward into the halls, feeling calmer than he had in almost a week. He hadn't been possessed. Whatever these dreams and missing memories were, they weren't something too bad.

XxX

September 1st, 1993, 5:30 pm

Voldemort looked out at the station, mentally marking down every student who would be important for the coming year. The third years had Hogsmeade visits now, which would be an ideal time to implant low level compulsions were it not for the Thief's Downfall. Instead, he'd need to be quite a bit more subtle to get around that problem. Thus came his newest set of projects. The research relating to the graveyard event he'd been able to recover from the Unspeakables he'd captured had certainly been useful. Without it, he couldn't have been certain about any of his initial moves. However, with it, his opening was all but trivial. His hands twitched three times, and a group of 6 green lights appeared in the air before flying off into the distance towards the castle. He felt his energy drain slightly as each settled into place. A moment later, he turned back towards his house, satisfied. It was time to truly begin.

A/N: Have some more magic system research, I insist! The magical aliasing trick isn't quite as powerful as it might seem, there are some downsides to using it which will become apparent shortly.

Please review!


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